Free-space optical communication link using a single Laguerre-Gaussian beam with tunable radial and azimuthal spatial indices generated by an integrated concentric circular antenna array.

We experimentally demonstrate a 10-Gbit/s free-space communication link using a single Laguerre-Gaussian (LG) beam with tunable radial and azimuthal modal indices generated by a photonic integrated circuit comprising two concentric uniform circular antenna arrays (UCAs). To tune the azimuthal modal indices ℓ of the generated beam, the azimuthal phase gradient inside each UCA is tuned. To tune the radial mode p of the generated beam, the amplitude ratio and phase difference between the two concentric UCA are tuned.

Temporally and longitudinally tailored dynamic space-time wave packets.

In general, space-time wave packets with correlations between transverse spatial fields and temporal frequency spectra can lead to unique spatiotemporal dynamics, thus enabling control of the instantaneous light properties. However, spatiotemporal dynamics generated in previous approaches manifest themselves at a given propagation distance yet are not arbitrarily tailored longitudinally. Here, we propose and demonstrate a new versatile class of judiciously synthesized wave packets whose spatiotemporal evolution can be arbitrarily engineered to take place at various predesigned distances along the longitudinal propagation path.

Tunable optical matrix convolution of 20-Gbit/s QPSK 2-D data with a kernel using optical wave mixing.

Compared to its electronic counterpart, optically performed matrix convolution can accommodate phase-encoded data at high rates while avoiding optical-to-electronic-to-optical (OEO) conversions. We experimentally demonstrate a reconfigurable matrix convolution of quadrature phase-shift keying (QPSK)-encoded input data. The two-dimensional (2-D) input data is serialized, and its time-shifted replicas are generated.